Unsaturated esters of substituted adipic acid and their production



Patented Aug. 31, 1948 UNSATURATED ESTERS OF SUBSTITUTED ADIPIC ACID ANDTHEIR PRODUCTION Harry de V. Finch, El qerrito, Calit, assignor to ShellDevelopment Company, San Francisco, Calii'., a corporation of'DelawareNo Drawing. Application October 16, 1944,

Serial No. 558,969

21 Claims. (Cl. 260-784) This invention relates to unsaturated estersand to methods for their production. More particularly the inventionpertains to the monomeric and polymeric unsaturated alcohol esters ofthe trimethyladipic acids wherein the methyl groups are substituted uponthe alpha and gamma carbon atoms, and to methods for the production ofsuch esters.

-The unsaturated esters of the invention are valuable compounds whichhave many important uses. Since they have physical and chemicalproperties which are surprisingly different from the properties of thecorresponding straight chain compounds, 0. g. the unsaturated esters ofadipic acid, they may be used in many applications for which the saidstraight chain compounds are not well suited. This difference inproperties may be attributed to the unique atomic configuration whichcharacterizes the esters of the-invention.

As is apparent, they contain an unsaturated group or groups attachedthrough an ester linkage to a highly branched carbon chain whichcontains a quaternary carbon atom, i. e. a carbon atom which is linkedthrough single valence bonds to four other carbon atoms. The compoundsof the invention are therefore particularly valuable plasticizers andtackifiers for-a wide variety of synthetic resins, being compatible witha large number of resinous materials and imparting valuable propertiesthereto. They are also useful textile assistants. Being highly toxic toinsects, they are useful as insecticides or as components ofinsecticidal compositions. Because of the presence of two types ofreactive groups, 1. e. the olefinic group and the ester group, theesters of the invention are valuable intermediates in the synthesis ofother organic compounds, thus offering an inexpensive source of avariety of compounds which contain a highly branched carbon chain. Aparticularly important use of the herein disclosed unsaturated estersresides, however, in their suitability for use as starting materials forthe preparation of synthetic resins, particularly allyl-type resins.This application of the esters of the invention is more fully describedhereinbelow. As stated, the. novel unsaturated esters which aredisclosed hereincomprise theesters of the unsaturated alcohols and thetrimethyladipic acids wherein the methyl groups are substituted upon thealpha and gamma carbon atoms. The said acids comprisealpha,aipha,-gamma-trimethyladipic acid and alpha,gamma,- gamma-trimethyladipic acid.These acids may be prepared in a variety of ways. They may be preparedespecially conveniently and inexpen- 2 sively, however, fromdihydrolsophorone, dihydroisophorol, or the isomerictrimethylcyclohexenes which may be produced by the dehydration ofdihydroisophorol. These compounds may be oxidized in such a manner as tobreak a carboncarbon bond in their cyclic structure, thereby effectingthe rupture of a carbon-carbon bond in the cyclic structure of thestarting material, and

giving rise to the formation of at least one tri- OH a 04, on, [o]OHS-(kg OHI g, CH:

7 OH: COOHOHrCH-CH2(BCOOH Ha Ha However, when the cleavage is in theopposite direction and the bond between the carbon atom bearing thehydroxyl group and the carbon atom adjacent tothe'monomethyl-substituted carbon atom is broken, the product isalpha,gamma,- gamma-trimethyladipic acid:

Both reactions usually occur when either dihydroisophorone ordihydroisophoroi is treated with an oxidizing agent, with the resultthat a mixture of isomeric trimethyladipic acids is formed as a product.The relative amount of the isomers formed is variable and depends uponthe particular oxidizing agent used and the operating conditions, suchas the temperature, pressure, presence or absence of a catalyst,reaction time, etc. It has been found, however, that when the oxidationis effected using nitric acid in the manner described hereinbelow areaction product is formed which comprises from about 60% to about 80%of alpha,alpha,gamma-trimethyladipic acid and from about to about 40% ofalpha,gamma,- gamma-trimethyladipic acid.

The oxidation of the'dihydroisophorone, dihydroisophorol or the mixtureof olefins obtainable by the dehydration of dihydroisophorol may beeffected through the agencyof a variety of oxidizing agents. Suitableoxidizing agents include, for example, potassium permanganate, potassiumdichromate, nitric acid and the like. It may also be carried outcatalytically in either the liquid or vapor phase, using oxygen oroxygen-containing gaseous mixtures, such as air, in the presence of acatalyst comprising compounds of cobalt, manganese, vanadium, nickel orchromium.

In a preferred method for oxidizing the hereinabove described compoundsto trlmethyladipic acid a quantity of dihydroisophorol may be heated ata temperature which is about the boiling temperature of the mixture witha molar excess of nitric acid having a concentration of about 50% nitricacid with or without the addition of a small amount of a catalyst suchas ammonium vanadate, cobalt acetate or manganese acetate. When thereaction is complete the reaction product may be fractionally distilledto separate the mixture of trimethyladipic acids therefrom. In anotherpreferred method trimethylcyclohexanone may be oxidized catalytically inthe liquid phase by passing oxygen or an oxygen-containing gas through asolution of trimethylcyclohexanone and a catalyst comprising, forexample, cobalt acetate or manganese acetate in a suitable solvent suchas glacial acetic acid. During the reaction period the reaction mixturemay be maintained at an elevated temperature, preferably a temperatureof between about 90 C. and about 110 C. The reaction product may then befractionally distilled, thereby separating the trimethyladipic acidsfrom the other constituents of the reaction mixture, 1. e. from theacetic acid solvent, unreacted ketone, and any higher acids or polymericmaterial which might be present. These acids may be used individually inthe preparation of the unsaturated esters of the invention or they maybe used as the mixture of isomers resulting from the hereinabovedescribed oxidative process.

The unsaturated alcohols which may be used in the synthesis of theherein disclosed unsaturated trimethyladipic acid esters comprise anyprimary, secondary or tertiary alcohols which contain at least oneunsaturated gr0up,.e. g. an olefinic group or an acetylenic group. Theesters may be, for example, those corresponding to the hypotheticalalcohols having a double bond of aliphatic character between two carbonatoms one of which is attached directly to an alcoholic hydroxyl groupas represented by the general formula Of the alcohols of this type apreferred subgroup consists of compounds having a terminal methylenegroup attached directly by an olefinic cohol, isopropenol, buten-1-ol-2,etc.

Examples of preferred alcohols are vinyl al- Examples of other alcoholsare propenl-ol-l, buten-1-ol-1, cyclohexen-l ol l, cyclopenten l ol 1,etc. Vinyl alcohol is a preferred specific alpha-unsat urated alcohol.

Another type of unsaturated alcohols which may be esterifled with thetrimethyladipic acids to form a particularly useful class of unsaturatedtrimethyladiplc acid esters comprises the unsaturated alcohols having anolefinic double bond of aliphatic character between two carbon atoms,one of which is attached directly-to a saturated carbon atom which inturn is attached directly to an alcoholic hydroxyl group, as representedby the general structural formula Preferred alcohols have a terminalmethylene group attached directly by an olefinic double bond to a carbonatom which is attached directly to a saturated carbinol carbon atom. asrepresented by the formula Representative examples of alcohols are thefollowing terminally unsaturated aliphatic alcohols of 3 to 8 carbonatoms per molecule and aralkenyl alcohols of 9 to 13 carbon atoms permolecule: ,allyl alcohol, methallyl alcohol, ethallyl alcohol,c'hloroallyl alcohol, buten-1-ol-3, penten-1-ol-3, hexen-1-ol-3,3-methyl-buten- 1-ol-3. 3-methyl-penten-l-ol-3, 2-methyl-buten- 1-01-3,2-methyl-penten-l-ol-3, 2,3-dimethylbuten-l-ol-3, hepten-1-ol-3,4-methyl-hexen-l- 01-3, 5-methyl-hexen-1 ol 3,4,4-dimethylpenten-1-ol-3, octen-1-ol-3, fi-methyl-heptenl-ol-3.4-rnethyl-hepten-1-ol-3, 4,4-dimethylhexen-1-ol-3,3-phenyl-propen-l-ol-3, 3-tolylpropen-1-ol-3, 3-xylyl-propen-1-ol-3.4-phenylbuten-l-ol-3, 4-tolyl-buten-l ol 3, 4-xylylbuten-1-ol-3,3-naphthyl-propen 1 ol 3, 4- chloro-buten-l-ol-B, pentadien-l,4-ol-3,hexen- 1-yn-5-o1-3, 2-methyl-penten-l-yn-4-ol-3, and2,5-dimet-hyl-hexadien-l,5-ol-4. Other alcohols are crotyl alcohol,tiglyl alcohol, S-chloro-buten- 2-01-1, cinnamyl alcohol,hexadien-2,4-ol-l, .hexadien-2,5-ol-l, butadien-2,3 -'ol-1, hexadien-3,5-01-2, Z-methyl hexen-2 ol l, 2 methylpenten-2-ol-l, 3,7 dimethyloctadlen-2,7-ol-l, cyclopenten-Z-ol-l, cyclohexen-2-ol-l, etc.

The acetylenic alcohols, i. 0. compounds which .contain a triple bond,comprise a third class of alcohols which may be reacted with thetrimethyladipic acids to form useful unsaturated trimethyladipic acidesters. Representative acetylenic alcohols are propargyl alcohol,pcntyn- 3-ol-2, 2-methylhexyn-3-ol-2, 3,7-dlmethyl-octyn-1en-6-ol-3,etc. Other alcohols are:

Buten-1-ol-4 (allyl carbinol) Penten-1-ol-5 2,6-dimethyl-octen-1-01-82,6-dimethyl-octen-2-ol-8 Hydrosorbyl alcohol Isohydrosorbyl alcoholUndecylenyl alcohol Dodecylenyl alcohol Oleyl alcohol Isooleyl alcoholVinyl allyl alcohol Sorbyl alcohol Geranyl alcohol Linoleyl alcoholLinolenyl alcohol Cyclopentenyhalcohol Cyclohexenyl alcohol Cyclohexenylcarbinol. etc.

These and other unsaturated alcohols may be reacted with thetrimethyladipic acids, using a single species of alcohol to prepare asingle species of trimethyladipie acid ester or. if desired, a varietyof difierent species of alcohols in admixture with each other to producea variety of species oi.

Monovinyl-alpha,gamma,gamma-trimethyl adipateDivinyl-alphalalphagamma-trimethyl adipateDivinyl-alpha,gamma,gamma-trimethyl adipateMonoisopropenyl-alpha,alpha,gamma-trlmethyl adipateMonoisopropenyl-alpha,gamma,gamma-trimethyl adipateDiisopropenyl-alpha,alpha,gamma-trimethyl adipate IDiisopropenyl-alpha,gamma,gamma-trimethyi adipate-Monopropargyl-alpha-alpha,gamma-trimethyl adipateMonopropargyl-alpha,gamma,gamma-trimethyl adipateDiprop'argyl-alpha,alpha,gamma-trimethyl adipate'Dipropargyl-alpha,gamma,gamma-trimethyl adipateMonoallyl-alpha,alpha,gamma-trimethyl adipateMonoallyl-alpha,gamma,gamma-trimethyl adipateDiallyl-alpha,alpha,gamma-trimethyl adipateDiallyl-alpha,gamma,gamma-trimethyl adipateMonomethallyl-alpha,alpha,gamma-trimethyl adipate jMonomethallyl-alpha,gamma,gamma-trimethyl adipateDimethallyl-alpha,alpha,gamma-trirnethyl adipateDimethallyl-aipha.samma,gamma-trimethyl adipateMonooleyl-alpha,alpha,gamma-trimethyi adipateMonooleyl-alpha,gamma,gamma-trimethyl adipateDioleyl-alpha,alpha,gamma-trimethyl adipateDioleyl-alpha,gamma,gamma-trimethyl adipate Methylvinyl-alpha,alpha,gamma-trimethyl adipate Methylisopropenyl-alpha,alpha,gamma-trimethyl adipate Methylpropargyl-a1pha,alpha,gamma-trimethyl adipate Allyl-methyl-alpha,alpha,gamma-trimethyl adipate Methylclclohexenyl-alpha,alpha,gamma-trimethyl adipate Vinylallyl-alpha,alpha,gamma-trimethyl adipate Isopropenyl methallylalpha,alpha,gamma trimethyl adipate Methylvinyl-alpha,gamma,gamma-trimethyl adipate Methylisopropenyl-alpha,gamma,gamma-trimethyl adipate Methylpropargyi-alpha,gamma,gamma-trimethyl adipate Allylmethyl-alpha.8amma,gamma-trimethyl adipate 1 Methylcyclohexenyl-alpha,gamma,gamma,tri-

methyl adipate Viny1' allyl-alpha,gamma,gamma-trimethyl adipateIsopropenyl methallyl-alpha,gamma,gamm-a-trimethyl adipate, etc.

Most of the methods which are customarily applied to the production ofunsaturated esters may be satisfactorily applied to the synthesis oi theunsaturated trimethyladipic acid esters of the invention. These estersmay be prepared, for example, by reacting atrimethyladipyl chloride withan unsaturated alcohol or with an unsaturated alkali metal alkoxide, e.g. sodium alloxide. Al-

'ternatively, the unsaturated esters of the invention may be synthesizedby reacting a trimethyladipic anhydrid with-an unsaturated alcohol.

Where the unsaturated alcohols are unstable, the

. corresponding esters may often be prepared by a simple ester exchangereaction, as by reacting a trimethyl adipic acid with an unsaturatedester of afatty acid, e. g. isopropenyl acetate. Where the unsaturatedalcohols are stable, however, the

unsaturated esters of'the invention may usually be most satisfactorilyprepared by direct esteriflcation of the trimethyladipic acid or themixture of isomeric trimethyladipic acids with the unsaturatedalcohol inthe presence of a suitable esterification catalyst. This reaction is inmost cases carried out more satisfactorily when provision is made forremoving the water which is a product of the esterification reactionsubstantially as soon as it is formed. The water-may be resubstancessuch as the mineral acids, e. g. sulfuric acid, hydrochloric acid,phosphoric acid and the like. Certain of the organic acids may also beused, suitable organic acids being, for example, benzene sulfonicacidsand para-toluene suli'onic acid. These may be added to the reactionmixture in any efiective amount. It is usually sumcient to add up toabout 1% by weight, based on the amount of trimethyladipic acid used.

The esteriflcation reaction may be carried out at any temperature whichis sumciently high to cause the desired reaction to take place. Asstated, temperatures which are about the boiling or reflux temperaturesof the reaction mixture are usually preferred. Higher or lowertemperatures may be used in a given case, however, if necessary.

The reaction is usually satisfactorily carried out at atmosphericpressure. However, superatmospheric or subatmospheric pressures may beemployed if desired.

Any suitable type of apparatus may be used. As pointed out, however, itis often desirable to use apparatus which is equipped withphase-separatingmeans as, for example, a separatory still head. Therelative amounts oi. the reacting substances are variable dependinglargely upon whether it is 7 desired to prepare the mono-ester or thedi-ester. When the mono-ester is to be prepared, the reactants arepreferably used in the ratioof about one mole of unsaturated alcohol permole of trimethyladipic acid. However, when it is desired to prepare thedi-ester, at least two moles of alcohol are used for each mole oftrimethyladipic acid.

Use of a greater amount of alcohol may be desirable in certain cases aswhere it is desired to complete the reaction in a relatively shortreaction time and to secure relatively high conversions oftrimethyladipic acid to ester.

One embodiment of the invention is represented by the following:

Divinyltrimethyl adipate may be prepared by heating a mixture comprisingthe herein described mixture of isomeric trimethyladipic acids and vinylacetate, preferably using an excess of the latter component. Thereaction is best carried out in the presence of a catalyst such asmercuric sulfate which may be introduced as such, or prepared in situ,as by the reaction between sulfuric acid and mercuric acetate. Thereaction mixture may be heated at refiux temperature until equilibriumis reached. The mixture may then be flash distilled to remove the excessvinyl acetate as well as the acetic acid formed by acid exchange as aproduct of the reaction, thereby leaving as a residue thedivinyltrimethyl adipate. This product may be purified by any suitablemeans, as by distillation under diminished pressure, preferably in thepresence of a polymerization inhibitor such as tannic acid.

Another embodiment is represented by the procedure Which may be used toprepare diallyltrimethyl adipate from dihyclroisophorol. This proceduremakes use of a mixture of alpha,alpha,- gamma-trimethyladipic acid andal'pha,gamma,- gamma-trimethyladipic acid and leads to the formationof amixture of the corresponding diallyl esters. In accordance with thisembodiment, dihydroisphorol or an equivalent substance such asdihydroisophoronc or the isomeric trimethylcyclohexenes which may beformed by the dehydration of dihydroisophorol is converted to theaforesaid mixture of isomeric trimethyl adipic acids by reaction with asuitable oxidizing agent. Although a variety of different oxidizingagents may be used for this purpose, an aqueous solution of nitric acid,0. g. a 50% aqueous solution, is preferred. -When a 50% aqueous solutionof nitric acid is used as the oxidizing agent, the oxidation ma besatisfactorily effected at a temperature which is about the boilingtemperature. of the reaction mixture. When the reaction is complete, thereaction mixture is fractionally distilled or otherwise treated toseparate the mixture of isomeric trimethyladipic acids.

The mixture or trimethyladipic acids prepared as described above maythenbc used without further treatment in the production of a. mixture ofisomeric unsaturated esters, e. g. the diallyl esters.

This esteriiication reaction may be carried out by heating a mixture ofthe aforesaid trimethyladipic acids, allyl alcohol, and an acidesteriflcation catalyst, preferably para-toluene sulfonic acid. Thetrimethyladipic acids and the allyl alcohol are preferably used in aratio which is such as to furnish at least two moles'of allyl alcoholfor each mole of trimethyladipic acid.

' Benzene is preferably added to the reaction mixture as awater-entraining agent and the reaction is preferably carried out atabout the boiling temperature of the reaction mixture, water beingseparated therefrom substantially as soon as it is 8 formed. When thereaction is complete the reaction mixture is distilled to separate thedially trimethyl adipates. i

As pointed out hereinabove, the allyl-type esters of the trimethyladipicacids are particularly vaiuable substances since they may be used asstart are those containing in the molecule a single.

polymerizable olefinic linkage such as styrene, vinyl halides,vinylidene halides, vinyl esters of saturated monocarboxylic acids,methyl acrylate, methyl methacrylate, allyl halides, allyl esters ofsaturated monocarboxylic acids, etc. Another important group consists ofunconjugated polymerizable compounds having in the molecule two or morenon-conjugated polymerizable unsaturated linkages such as unsaturatedaliphatic polyesters of saturated polybasic acids, polyesters ofsaturated polyhydric alcohols with unsaturated organic acids, and estersof unsaturated alcohols with unsaturated aliphatic acids. Otherpolymerizable unsaturated compounds are those containing in the moleculeone or more polymerizable organic radicals and one or more inorganicradicals or elements as exemplified by the vinyl, allyl and methallylesters of phosphoric acid and of the ortho acids of silicon, boron, etc.Another important group of co-polymerizable compounds consists of thosehaving in the molecule two or more, preferably two, conjugatedunsaturated polymerizable carbon-to-carbon linkages such as conjugatedbutadiene, conjugated chlorobutadiene, isoprene, the other conjugatedpentadienes, the conjugated hexadienes. their homologues, analogues andsuitable substitution products. Particularly valuable co-polymers arethose of the compounds of the invention with one or more allyl-typepolyesters of polycarboxylic acids, particularly allyl-type polyestersof aromatic polycarboxylic acids, e. g. diallyl phthalate and the like.Other valuable co-polymers of the preferred class are those withallyl-typev polyesters of ethereal oxygen-containing polycarboxiicacids,

e. g. diailyl diglycolate.

The compounds of the invention can be polymerized and co-polymerized byoxygen-containing polymerization catalysts. Benzoyl peroxide has beenfound satisfactory for this purpose. Other polymerization catalysts areacetyl peroxide, benzoyl acetyl peroxide, lauryl peroxide,

dibutyryl peroxide, succinyl peroxide, sodium peroxide, barium peroxide,tertiary alkyl hydroperoxides, such as tertiary butyl hydroperoxide,peracetic acid, perphthalic acid, sodium peroxide. perborates,persulfates, ozone and oxygen, The compounds can be polymerized in thepresence of their own peroxides, or of their ozonides. Another class ofpolymerization catalysts consists of the di(tertiary alkyl) peroxides,notably di(tertiary butyl) peroxide, as described and claimed in theco-pending application of Vaughan and Rust, Serial Number 481,052, filedMare}; 29. 1943, now U. S. Patent 2,426,476, which is acontinuation-in-part of their co-pending application Serial Number,474.224, filed January 30, 1943, now U. S. Patent 2,395,523. Metals andmetallic salts may be used as polymerization catalysts. If desired,mixtures of polymerization catalysts can be used, a suitable mixturebeing that of benzoyl peroxide and hydrogen peroxide. In some cases itmay be desirable to conduct the polymerization in the concurrentpresence of both a catalyst and an inhibitor of polymerization. Theamount of peroxide catalyst used will ordinarily be between about 0.01%and about although it is not necessarily limited to this range. In stillother cases it may be unnecessary to use any catalyst at all.

Polymerization is usually energized by the application of heat, althoughboth heat and light may be used, and in some cases, light may besufflcient. Temperatures between about 60 C.

and about 150 C. are preferred, although higherthe dispersion method isemployed, it may be deworked and eventually substantially completelypartially polymerized material. Where the modifiers are not added to themonomer, they can be incorporated with preformed polymer by grindins.mixing or milling on heated rolls, or by coprecipitation from a commonsolvent.

Polymers and co-polymers can be produced in accordance with theinvention which are characterized by excellent resistance to the actionof physical and chemical agents. Resins can be produced which are clear,water-white, hard and iniusible. Many of the polymers possessfilmforming properties and adhere well to metal and to many other kindsof surfaces. They can be used as the basis for valuable coatingcompositions. Some of the solid resinous products of the invention canbe used as glass substitutes. Massive castings can be subjected tomachine operations. Many of the resins can be used in extrusion,injection molding and compression mold ing processes.

The process of the invention for the production of unsaturated esters ofthe trimethyladipic acids wherein the methyl groups are substituted uponthe alpha and gamma carbon atoms is illustrated by the followingexamples wherein the parts are parts by weight.

Example I of about 1 mole of trimethyladipic acid to 1 mole of allylalcohol, together with a small amount of para-toluene sulfonic acid anda sufficient amount of benzene to serve as a carrier for the waterproduct. The water layer was removed from the phase separating headsubstantially as soon as it was formed. Completion of the repolymerized.The syrup may, for instance, be

transferred to a mold of any desired configuration and again subjectedto polymerization conditions, or it may be used in coating operations,or in impregnating bibulous, e. g. fibrous, material, which in turn maybe used in the production of laminates. Unreacted monomer maybeseparated from its mixture with polymer by solvent extraction,distillation or other methods. The separated polymer may then be workedup in any known or specialmanner. In the case. of many compounds,particularly in the case of the polymerization of compounds having twoor more non-conjugated polymerizable unsaturated linkages in themolecule, the separated polymer may be capable of furtherpolymerization. Such compounds can be rendered infusible and insolublein' common nonreactive solvents.

Polymers and co-polymers of the invention can be modified by admixturewith other synthetic resins, natural resins, cellulose derivatives,-anddrying oils. Preferred modifiers are film-formin substances. Examples ofsynthetic resins in addition to polymers of the polymerizableunsaturated organic compounds illustrated hereinabove are alkyd resins,urea-aldehyde resins, phenolaldehyde resins and syntheticlinearsuper-polyamides and polyester-amides. There may also be presentone or more plasticizers, stabilizers, lubricants, dyes, pigments, orfillers. Where the modiflers do not react with, or otherwise adverselyaffect, the ingredients of the reactionmixture,

they may be added to the monomer or to the Elzample IIAllylvinyltrimethyl adipate is prepared by forming a mixture ofallylhydrogen adipate, vinyl acetate, mercuric acetate and sulfuricacid. This mixture is refluxed for about one hour, following which it.is distilled at atmospheric pressurepntil the vinyl acetate and aceticacid have been removed. The residueis then distilled at subatm'os- 4pheric pressure, preferably in the presence of tannic acid, in order toseparate the allylvinyltrimethyl adipate.

Example III A mixture of dimethallyl-alpha,alpha,gammatrimethyl adipate,and dimethallyl-alpha,-

. gamma,gamma-trimethyl adipate is prepared by Example IV Example V Amixture of diallyl-alpha.alpha,gamm'a-trimethyl adipate anddiallyl-alpha,gamma,gammatrlmethyl adipate was prepared from dihydro-'isophorol or from its equivalents dihydroisophorone or themixture ofisomeric trimet'hylcyclohexenes formed by the dehydration oidihydroisophorol. This preparation was accomplished by adding a quantityof dihydroisophorol. or of its equivalents, to a quantity of 50% nitricacid contained in a suitable reaction vessel.

The dihydroisophorol was added at such a rate as to effect a smoothreaction and maintain the temperature of the reaction mixture at aboutthe boiling temperature. The reaction mixture was preferably stirredduring the addition of the dihydro'isophorol. When the reaction wascomplete the reaction mixture was fractionally distilled, therebyseparating the trimethyladipic acid product from the excess nitric acid,water and other by-products. The trimethyladipic acid fraction boiled at170 C. to 180 C. at 3 mm. Upon standing it crystallized to form a solidproduct melting between 45 C. and 55 C. The equivalent weight of theacid fraction was determined to be 98.5 (theory, 94).

The :composition oi! the mixture of isomeric trimethyladipic acidsobtained in this manner was determined by converting the mixture to amixture of trimethylcyclopentanones, which mixture could be separated byfractional distillation. The cyclopentanones were prepared by heatingabout 1 part by weight 01' barium hydroxide octahydrate with about-l5parts of the trimethyladipic acid mixture at 200 C. to 285 C. Theorganic product was iractionally distilled, thereby effecting itsseparation into two products which were identified as2,4,4-trimethy1cyclopentanone and 3,5,5-trimethylcyclopentanone. Therelative amounts of these two derivatives were such as to indicate thatthe original mixture or isomeric trimethyladipic acids from which thecyclopentanones were formed comprised from about 60% to about 80% ofalpha, alpha, gammatrimethyladipic acid and from about 20% to about 40%of alpha,gamma,gamma-trimethyladipic acid. The mixture of isomerictrimethyladipic acids obtained in this manner was converted to a mixtureof the corresponding di-allyl asters by reaction with allyialcohol,using at least two moles of allyl alcohol for,each mole oftrimethyladipic acid. The procedure used was otherwise substantially thesame' as that employed for the preparation or monoallyltrimethyl adipateas described in Example I. Distillation of the reaction product resultedin the separation of the desired diallyl esters, which boiled at 100 C.to 105 C. at 1 mm. and had a saponification value (eq./100 gr.) of0.750, and a bromine number (gr./100- Br.) of 118. The mixture of estersanalyzed 66.8% C and 9.0% H, the theoretical analysis being 67.2% Cand8.95% H- I Example VI The diallyltrimethyladipic acid esters obtainedsubstantially as described in Example Vwere polymerized 'by forming amixture comprising the said esters together with about 5% by weight ofbenzoyl peroxide. The said mixture was heated at about 65 C. for from 5to 2.0 hours.

The polymeric product was an infusible solid which was light yellow incolor.

Example VII The diallyltrimethyladipic acid esters obtained as describedin Example V were polymerized using substantially the same procedure asdescribed 7 in Example VI with the exception that only about 2% byweight of benzoyl peroxide catalyst was used. In this case the mixturehad set to a gel after having been heated at C. for about 5- hours.After about 6 days a light yellow clear infusible polymer was obtained.

I claim as my invention:

1. A \polymerlzable ester of an alcohol having an aliphatic multiplelinkage between two carbon atoms and trimethyladipic acid wherein themethyl groups are substituted upon the alpha and gamma carbon atoms.

2. A polymer of a polymerizable ester of an aliphatic alcohol having amultiple linkage between two carbon atoms and trimethyladipic acidwherein the methyl groups are substituted upon the alpha and gammacarbon atoms.

3. A polymerize-bio esteroi an aliphatic monohydric alcohol of 3 to 8carbon atoms per molecule having an olefinic linkage between two carbonatoms. one 01 which is a terminal carbon atom, and trimethyladipic acidwherein the methyl groups are substituted upon the alpha and gammacarbon atoms.

4. An ester of an unsaturated alcohol having an aliphatic multiplelinkage between two carbon atoms and alpha,alpha,gamma-trimethyladiptcacid.

5. An ester of an unsaturated alcohol having an aliphatic multiplelinkage between two carbon atoms and alpha,gamma,gamma-trimethyladipicacid.

6. An ester of a vinyl alcohol and trimethyladipic acid wherein themethyl groups are substituted upon the alpha and gamma carbon atoms. 1

'7. A monoester of an allyl alcohol and trimethyladipic acid wherein themethyl groups are substituted upon the alpha and gamma carbon atoms.

8. Monoallyl-alpha,alpha,gamma trimethyl adipate.

9. A. mixture of isomeric monoallyl esters which comprises from about60% and about 80% of monoallyl-alpha,alpha,gamma-trimethyl adipate andbetween about 20% and about 40% monoallyl alpha,gamma,gamma-trimethyladipate.

10. A diallyl ester of trimethyladipic acid wherein the methyl groupsare substituted upon the alpha and gamma carbon atoms.

11. A polymeric diallyl ester of trimethyladipic acid wherein the methylgroups are substituted upon the alpha and gamma carbon atoms.

12. A diester of a mono-olefinic monohydric aliphatic hydrocarbonalcohol of 3 to 8 carbon atoms per molecule having a terminal methylenegroup attached by the oleflnic double bond to a carbon atom which isdirectly attached to the carbinol carbon atom and trimethyladiplc acidwherein the methyl groups are substituted upon the alpha and gammacarbon atoms.

. 13. 40% of diallyl-alpha,gamma,gamma-trimethyl a-dipate.

15. A process for the production of unsaturated esters which comprisesheating a mixture of an unsaturated alcohol having an aliphatic multiplelinkage between two carbon atoms and trimethyladipic acid wherein themethyl groups are substituted upon the alpha and gamma carbon atoms, inthe presence of an acid esterification catalyst at the boilingtemperature of the reaction mixture, and removing the water produced.

16. A process for the production of an ester ofalpha,alpha,gamma-trimethyladi-pic acid and an unsaturated alcoholhaving an aliphatic multiple linkage between two carbon atoms, one ofwhich is a terminal carbon atom, which comprises heating a mixture of anunsaturated alcohol and alpha,alpha,gamma-trimethyladipic acid, in 'thepresence of an acid esterification catalyst at the boiling temperatureof the reaction mixture, and removing the water produced.

17. A process for the production of esters which comprises heating amixture of alpha,- gamma,gamma-trimethyladipic acid and an allphaticunsaturated alcohol having an olefinic linkage between two carbon atoms,one of which is a terminal carbon atom, in the presence of an acidesterification catalyst at the boiling temperature of thereactionmixture, and removing the water produced.

18. A method for the preparation of a monoallyl ester of trimethyladipicacid wherein the methyl groups are substituted upon the alpha and gammacarbon atoms which comprises heating a mixture of allyl alcohol and atrimethyladipic acid wherein the methyl groups are substituted upon thealpha and gamma carbon atoms using the reactants in the relative-amountsof about 1 mole of trimethyladipic acid to about 1 mole of allylalcohol, in the presence of an acid esterification catalyst at theboiling temperature of the reaction mixture, and removing the waterproduced.

19. A method for the preparation of a diallyl ester of trimethyladipicacid wherein the methyl groups are substituted upon the alpha and gammacarbon atoms which comprises heating a mixture of allyl alcohol and atrimethyladipic acid wherein the methyl groups are substituted upon thealpha and gamma carbon atoms using the reactants in the relative amountsof one mole oftrimethyladiplc acid to about 2 moles of allyl alcohol, inthe presence of an acid esteriflcation catalyst at the boilingtemperature of the reaction mixture, and removing the water produced.

20. A process for the production of polymers of allyl esters whichcomprises heating a mixture of allyl alcohol and trimethyladipicacidwherein the methyl groups are substituted upon the alpha and gammacarbon atoms in the presence of an acid esterification catalyst at theboiling temperature of the reaction mixture, removing the water producedand polymerizing the resulting allyl ester. I

21. A process for the production of diallyltrimethyl adipates whichcomprises reacting a mixture of trimethyadipic acids which comprisesfrom about 60% to about 80% alpha,a1pha,- gamma-trimethyladipic acid andfrom about to about 40% alpha.gamma,gamma-trimethyladipic acid, withallyl alcohol using a reaction mixture which contains about 1 mole ofthe. said mixture of isomeric trimethyladipic acids to at least 2 molesof allyl alcohol together with an acid esterification catalyst, heatingthe said reaction mixture at a temperature which is substantially itsboiling temperature, separating the water which is formed as a productof the -re-' action substantially as soon as it is formed-andfractionally distilling the dehydrated reaction mixture, thereby forminga product which essentially comprises from about to about ofdiallyl-alpha,alpha,gamma-trimethyl adipate and from about 20% to about40% of alpha,- g-amma,gamma-trimethyladipic acid.

HARRY DE V. FlNCH.

nnrnncnca's CITED The following references are of record in th file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Qudrat-i-Khuda et 2.1.: Abstractin Chem. Abstracts, 34, 993 (1940).

Beilstein, Handbuch der organischen Chemie, vol. 2, page 715.

